The present invention relates to a wiper rubber, to a process for the production of a wiper rubber, to a wiper rubber thus produced, and to a resultant windshield wiper.
Wiper rubbers for windshield wipers are generally composed of elastomers and designed to conform to the shape of glazing of a vehicle, and to remain flexible at various temperatures.
Ethylene-propylene-diene rubber (EPDM) and ethylene-propylene rubber (EPM) are synthetic rubbers having in essence a saturated main carbon chain, and are allocated in accordance with DIN ISO 1629 to the M group of synthetic rubbers.
Ethylene-propylene-diene rubber and ethylene-propylene rubber have various advantageous properties, for example high resistance to temperature change. However, they also have a high coefficient of friction, which causes noise during wiping and rapid wear of the wiper rubber.
It is known that the surface of wiper rubbers can be chlorinated in order to reduce friction.
Since, however, ethylene-propylene-diene rubber and ethylene-propylene rubber have a saturated main carbon chain and therefore have no double bonds in the main chain, it is not possible to modify the surface of these via addition reactions, such as chlorination.
The document EP 2 308 725 A1 describes a process for the production of a wiper rubber in which a wiper rubber made of a non-diene-based rubber is irradiated in order to generate free-radical bonding sites, and is coated with monomers, which are linked to the free-radical bonding sites by graft polymerization.